Sökning: "quasi-Newton method"

Visar resultat 1 - 5 av 18 avhandlingar innehållade orden quasi-Newton method.

  1. 1. On Methods for Solving Symmetric Systems of Linear Equations Arising in Optimization

    Författare :Tove Odland; Anders Forsgren; William W. Hager; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; symmetric system of linear equations; method of conjugate gradients; quasi-Newton method; unconstrained optimization; unconstrained quadratic optimiza- tion; Krylov subspace method; unnormalized Lanczos vectors; minimum-residual method; symmetriska linjära ekvationssystem; konjugerade gradientmetoden; kvasi- Newtonmetoder; optimering utan bivillkor; kvadratisk optimering utan bivillkor; Kry- lovunderrumsmetoder; icke-normaliserade Lanczosvektorer; minimum-residualmetoden; Mathematics; Matematik;

    Sammanfattning : In this thesis we present research on mathematical properties of methods for solv- ing symmetric systems of linear equations that arise in various optimization problem formulations and in methods for solving such problems.In the first and third paper (Paper A and Paper C), we consider the connection be- tween the method of conjugate gradients and quasi-Newton methods on strictly convex quadratic optimization problems or equivalently on a symmetric system of linear equa- tions with a positive definite matrix. LÄS MER

  3. 2. Numerical Algorithms for Optimization Problems in Genetical Analysis

    Författare :Kateryna Mishchenko; Sverker Holmgren; Dmitrii Silvestrov; Lars Rönnegård; Ann-Charlotte Berglund Sonnhammer; Mälardalens högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantitative Trait Loci QTL ; restricted maximum likelihood REML ; variance components; average information AI matrix; Local optimization; Quasi-Newton method; Active Set method; Hessian approximation; BFGS update; Applied mathematics; Tillämpad matematik; Matematik tillämpad matematik;

    Sammanfattning : The focus of this thesis is on numerical algorithms for efficient solution of QTL analysis problem in genetics.Firstly, we consider QTL mapping problems where a standard least-squares model is used for computing the model fit. LÄS MER

  4. 3. Utilizing Problem Structure in Optimization of Radiation Therapy

    Författare :Fredrik Carlsson; Anders Forsgren; Edwin Romeijn; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optimization; intensity-modulated radiation therapy; conjugate-gradient method; step-and-shoot delivery; column generation; quasi-Newton method; regularization; sequential quadratic programming; Optimization; systems theory; Optimeringslära; systemteori;

    Sammanfattning : In this thesis, optimization approaches for intensity-modulated radiation therapy are developed and evaluated with focus on numerical efficiency and treatment delivery aspects. The first two papers deal with strategies for solving fluence map optimization problems efficiently while avoiding solutions with jagged fluence profiles. LÄS MER

  5. 4. Numerical algorithms for nonlinear eigenproblems with eigenvector nonlinearities

    Författare :Parikshit Upadhyaya; Elias Jarlebring; Robert Corless; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; numerical algorithms; nonlinear eigenproblems; multiparameter eigenvalue problem; nonlinear eigenvalue problem; eigenvector nonlinearities; nepv; scf; p-laplacian; quasi-newton; Numerical Analysis; Numerisk analys;

    Sammanfattning : Eigenproblems and their nonlinear generalizations appear as important problems in a wide variety of fields, ranging from quantum chemistry and vibration analysis to macroeconomics and data science. Hence, the development and analysis of numerical algorithms to solve such problems has a broad multiplicative effect on our ability to answer several crucial scientific questions. LÄS MER

  7. 5. Algorithms in data mining using matrix and tensor methods

    Författare :Berkant Savas; Lars Eldén; Lieven De Lathauwer; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Volume; Minimization criterion; Determinant; Rank deficient matrix; Reduced rank regression; System identification; Rank reduction; Volume minimization; General algorithm; Handwritten digit classification; Tensors; Higher order singular value decomposition; Tensor approximation; Least squares; Tucker model; Multilinear algebra; Notation; Contraction; Tensor matricization; Newton s method; Grassmann manifolds; Product manifolds; Quasi-Newton algorithms; BFGS and L-BFGS; Symmetric tensor approximation; Local intrinsic coordinates; Global embedded coordinates; ; Numerical analysis; Numerisk analys;

    Sammanfattning : In many fields of science, engineering, and economics large amounts of data are stored and there is a need to analyze these data in order to extract information for various purposes. Data mining is a general concept involving different tools for performing this kind of analysis. LÄS MER